Gold M E, Wood K S, Byrns R E, Buga G M, Ignarro L J
Department of Pharmacology, University of California School of Medicine, Los Angeles 90024.
Am J Physiol. 1990 Dec;259(6 Pt 2):H1813-21. doi: 10.1152/ajpheart.1990.259.6.H1813.
The objective of this study was to ascertain whether endothelium-dependent relaxation and guanosine 3',5'-cyclic monophosphate (cGMP) formation in bovine pulmonary artery are dependent on L-arginine. Arterial rings responded to acetylcholine and A23187 with increased cGMP accumulation and relaxation and showed resting L-arginine levels of approximately 300 microM. Addition of L-arginine failed to cause relaxation or cGMP accumulation. Arterial rings incubated under tension at 37 degree C for 24 h showed a three- to fourfold decline in L-arginine levels, and this decline was accompanied by a similar decline in resting cGMP levels as well as complete refractoriness to endothelium-dependent relaxation and cGMP formation in response to acetylcholine and A23187, without alteration of responsiveness to nitric oxide, s-nitrosothiols, or nitroglycerin. The endothelium in 24-h incubated arterial rings was normal morphologically, as assessed by scanning electron microscopy. L-Arginine caused endothelial-dependent relaxation and cGMP formation in L-arginine-depleted rings, which was antagonized by oxyhemoglobin and methylene blue. Bovine aortic endothelial cells grown in L-arginine-deficient medium supplemented with D-arginine during the final 24 h of growth failed to generate endothelium-derived nitric oxide, as assessed by bioassay cascade. L-Canavanine, but not L-lysine or L-ornithine, protected against the decline in L-arginine and cGMP levels and loss of endothelium-dependent relaxation that was characteristic of 24-h incubated arterial rings. The pharmacological properties of L-arginine were shared by L-arginine ethyl ester, L-arginine methyl ester, and L-homoarginine but not N-alpha-benzoyl-L-arginine ethyl ester or L-canavanine. These observations indicate that L-arginine or a structural analogue may be obligatory for endothelium-dependent relaxation and cGMP formation.
本研究的目的是确定牛肺动脉中内皮依赖性舒张和鸟苷 3',5'-环磷酸（cGMP）的形成是否依赖于 L-精氨酸。动脉环对乙酰胆碱和 A23187 有反应，cGMP 积累增加且舒张，静息 L-精氨酸水平约为 300 μM。添加 L-精氨酸未能引起舒张或 cGMP 积累。在 37℃张力下孵育 24 小时的动脉环，L-精氨酸水平下降了三到四倍，这种下降伴随着静息 cGMP 水平的类似下降，以及对乙酰胆碱和 A23187 引起的内皮依赖性舒张和 cGMP 形成完全不应答，而对一氧化氮、S-亚硝基硫醇或硝酸甘油的反应性未改变。通过扫描电子显微镜评估，孵育 24 小时的动脉环中的内皮在形态上是正常的。L-精氨酸在 L-精氨酸耗竭的环中引起内皮依赖性舒张和 cGMP 形成，这被氧合血红蛋白和亚甲蓝所拮抗。在生长的最后 24 小时补充 D-精氨酸的 L-精氨酸缺乏培养基中生长的牛主动脉内皮细胞，通过生物测定级联评估，未能产生内皮源性一氧化氮。L-刀豆氨酸，但不是 L-赖氨酸或 L-鸟氨酸，可防止 L-精氨酸和 cGMP 水平的下降以及孵育 24 小时的动脉环特有的内皮依赖性舒张丧失。L-精氨酸乙酯、L-精氨酸甲酯和 L-高精氨酸具有与 L-精氨酸相同的药理特性，但 N-α-苯甲酰-L-精氨酸乙酯或 L-刀豆氨酸则不具有。这些观察结果表明，L-精氨酸或其结构类似物对于内皮依赖性舒张和 cGMP 形成可能是必需的。
